It has previously been proposed to provide an electronic display of outputs indicating the state of various sensors, or numerical values representative of measured operation, or operating conditions, or of other parameters to be indicated, for example clock time. In one such arrangement--see U.S. Pat. No. 3,988,730, Valker (to which German No. 25 55 828 corresponds),--a ring counter is provided for cyclicallyinterrogating various sensors distributed within a motor vehicle. The sensors measure conditions, and parameters occurring within the vehicle and provide corresponding electrical output signals. The measured values, as represented by the output signals are then applied in the form of electrical control signals, in time sequence, over a logic circuit to a plurality of light emitting diodes (LEDs), in order to provide an optical indication of the state or condition of the various apparatus and devices monitored by the respective sensors.
The system as described requires a separate control conductor or line for each one of the LEDs from the centrally located logic circuit. It is only possible to sense values with this circuit which signal a binary state, that is, ON or OFF. Continuous variable parameters, such as, for example, speed, fuel level in a fuel tank, and the like, cannot be indicated with this circuit arrangement.